Four Novel Cycloartane Glycosides from Astragalus oleifolius

Abstract

Four novel cycloartane-type triterpene glycosides, macrophyllosaponins A-D (1-4) were isolated from the roots of Astragalus oleifolius. By means of chemical (acetylation, alkaline hydrolysis) and spectroscopic methods (IR, 1D- and 2D-NMR, FABMS), their structures were established as 3-O-alpha-L-rhamnopyranosyl-24-O-(4"-O-acetyl)-beta-D-xylopyranosyl-1 alpha,3 beta,7 beta,24(S), 25-pentahydroxycycloartane (1), 3-O-alpha-L-rhamnopyranosyl-24-O-beta-D-xylopyranosyl-1 alpha,3 beta, 7 beta,24(S), 25-pentahydroxycycloartane (2), 3-O-alpha-L-rhamnopyranosyl-25-O-beta-D-glucoyranosyl-1 alpha, 3 beta,7 beta,24(S),25-pentahydroxycycloartane (3), and 3-O-alpha-L-rhamnopyranosyl-24-O-(2-O-beta-D-xylopyranosyl) -beta-D-xylopyranosyl-1 alpha,3 beta,7 beta,24(S), 25-pentahydroxycycloartane (4).

Cycloartane-Type Saponins from Astragalus Tmoleus var. Tmoleus

“…Chemotaxonomic significance: According to the APG III (2009) classification [22], four families belong to the Fabales order, Fabaceae, Polygalaceae, Quillajaceae and Surinaceae. Among them, Fabaceae is the only family containing cycloartane-type (9,19 cyclo-lanostane) triterpenoids, which are common in the genus Astragalus [3][4][5][6][7][8][9][10][11][12]. Our results confirm that triterpene saponins with a cycloartane-type skeleton might be chemotaxonomically significant for the genus Astragalus [19].…”

“…Roots of these plants are used in Turkish folkloric medicine as an antiperspirant, diuretic, and tonic drug and for the treatment of diabetes mellitus, nephritis, leukemia, and uterine cancer [2]. Earlier investigations of Turkish Astragalus species resulted in the isolation of 45 cycloartane glycosides including five different aglycones and about 30 new compounds [3][4][5][6][7][8][9][10][11][12].…”

Cytotoxic Activity of Crude Extracts fromAstragalus Chrysochlorus(Leguminosae)

“…In Anatolia, an aqueous extract of Astragalus roots are traditionally used for treatment of leukemia and wound-healing (3). In addition, the main use of Astragalus plants is the production of the economically important gum tragacanth (7).…”

Cycloartane Glycosides from Sutherlandia frutescens

“…The chemical shifts of a set of carbon resonances, corresponding to the side chain at C-17 (from C-20 to C-27) and the β-glucopyranosyl moiety, are completely identical to those of known glycosides that possess a 24 S ,25-dihydroxy side chain in which the β- d -glucopyranosyl moiety is attached to the tertiary C-25 OH group. 13 The location of the OH groups at C-1 and C-3 on ring A was indicated by DQF-COSY, showing a coupling network from H-1 → H-2 → H-3. In the HMBC spectrum of 1 , the characteristic H-19 at δ H 2.89 correlated with one oxygenated carbon at δ C 84.8 (C), two olefinic carbons at δ C 135.9 (C) and 121.1 (CH), and a methine at δ C 53.1 that was assumed to be C-8.…”

“…A DEPT NMR experiment permitted differentiation of the 36 resonances into seven methyl, nine methylene, 14 methine, and six quaternary carbons, of which 30 were attributed to a triterpene skeleton and six to a β-glucopyranosyl moiety (Table 1). 12,13 The β configuration of the glucopyranose was evident by its anomeric proton resonance at δ H 5.24 (d, J = 7.6 Hz, H-1) in the 1 H NMR spectrum (Table 2). Regarding the aglycone moiety, typical resonances include six tertiary methyl groups at δ H/C 0.71/15.5, 1.57/21.7, 1.54/24.6, 1.17/27.4, 1.03/24.0, and 0.75/20.0, one secondary methyl at δ H/C 0.95/19.2, four oxygenated methine at δ H/C 3.83 (br, s)/77.0, 3.86 (d, J = 9.7 Hz)/78.7, 4.28/72.0, and 4.30/75.8, two oxygenated quaternary carbons at δ C 81.3 and 84.8, and one double bond at δ C 135.9 (C) and 121.1 (CH), indicating a polyhydroxylated cycloartane-like triterpene skeleton.…”